SOLUTION: The average (arithmetic mean) of 80, 83, 89, and x is the same as the average of 80, 83, and 86. What is the average of 82 and x? (A)80 (B) 81 (C) 82 (D) 83 (E) 84

Algebra ->  Average -> SOLUTION: The average (arithmetic mean) of 80, 83, 89, and x is the same as the average of 80, 83, and 86. What is the average of 82 and x? (A)80 (B) 81 (C) 82 (D) 83 (E) 84       Log On


   

Question 311486: The average (arithmetic mean) of 80, 83, 89, and x is the same as the average of 80, 83, and 86. What is the average of 82 and x?
(A)80 (B) 81 (C) 82 (D) 83 (E) 84
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
The average (arithmetic mean) of 80, 83, 89, and x is the same as the average of 80, 83, and 86.
:
%2880%2B83%2B89%2Bx%29%2F4 = %2880%2B83%2B86%29%2F3
:
%28252%2Bx%29%2F4 = %28249%29%2F3
Cross multiply
3(252+x) = 4(249)
:
756 + 3x = 996
:
3x = 996 - 756
:
3x = 240
x = 240%2F3
x = 80
:
What is the average of 82 and x?
%2882%2B80%29%2F2 = 81